The importance of therapeutic exercise is widely accepted for a variety of human disabilities. Exercise plays a crucial role in the rehabilitation of patients suffering from various injuries. Physical therapists regularly provide rehabilitative professional care that individually tailors exercise programs to meet a patient's needs. Rehabilitative exercise programs differ depending on the type and amount of damage to the injured area, stage of tissue healing, age of the person, and level of function of the individual prior to injury.
In many cases, lack of exercise is a contributing factor, if not the primary predisposing factor influencing injury in an adult. The human body was meant to move. As people get older they move less and sit more. Movement increases blood supply which facilitates greater nutrients to muscle and bone and maintains the health of the living tissue. The lack of movement results in poor distribution of nutrients to muscle and bone and the body in general becomes weaker and more susceptible to injury. Hospital studies have shown that a person on continuous bed rest can lose up to thirty percent of their lean body mass in just three weeks.
When a person becomes unaccustomed to strenuous chores after a long winter, and then spends a spring weekend strenuously working in the yard digging holes, planting flowers and pulling weeds, that person will likely find himself taking aspirin and complaining of an aching shoulder, back or both to recover from the resulting pain. Sometimes the soreness goes away, but all too often the soreness persists and requires medical attention.
Regular exercise may keep the body in good shape, but not all exercise is equally effective. In fact, many exercise devices on the market, particularly in health and athletic clubs, are less effective than patrons may assume. That is not to say that the majority of the exercise equipment in the health clubs is not beneficial when used with the guidance of a trainer. The problem is that most available equipment in health clubs train in predominantly linear, single plane movement and are limited to isolating one muscle group while allowing other muscle groups to rest. An example of this type of exercise is the use of a curl bench, commonly referred to as a "preacher" bench. The preacher bench allows one to isolate the biceps brachii and does not require much, if any, trunk, hip, or leg activity. This type of training may be appropriate for an athlete or one who has a balanced workout regimen, but isolated, planar movement is not how the body typically moves.
The body rarely moves in just one plane and often requires multiple muscle groups to work together. Most body movement involves rotation and diagonal patterns of movement. Imagine trying to bring a fork to your mouth without any rotation of your hand or wrist. Think of taking off a sweatshirt or pulling on a pair of socks with only linear single planar movement--difficult? Yes| If we moved in single planes it would be easy to construct a mechanical hand, foot or leg to mirror human movement, but it is very difficult to replicate human movement because it is not defined through one- or two-dimensional movement. The myriad muscles surrounding our joints allow us to move in limitless but controlled patterns. With the freedom of movement in our extremities, comes a demand for stability throughout our trunk and base. For example, when we open a door we are not just pulling in a straight line with our arm. The feet are planted and as the hand-arm-shoulder complex moves, the trunk, hips and knees need to stabilize and create a base from which we can generate enough force to open the door. This stabilizing force applied to the trunk, hips and knees is not a push-pull movement, but is rather a rotational movement about the trunk. A lot of shoulder, knee, ankle and particularly back injuries occur as a result of excessive rotational force demands placed on the body.
Proprioceptive Neurofacilitation, PNF, is a school of thought within the physical therapy art that includes the assumption that the best form of rehabilitation for musculoskeletal injuries occurs in diagonal patterns through multiple planes of movement. However, this treatment technique requires a purely hands-on, manual approach, extremely demanding of therapist skill and training. The therapist presently practicing PNF must take the patient through the motions and provide appropriate resistance for the patient's need and present physical limitations. There is therefore a need in the exercise equipment art, therapeutic or not, for an apparatus that provides structured, multi-axial movement to the average healthy person or to someone recovering from back, shoulder, knee or hip injury.
While the available art provides attempts at developing portable equipment that embodies movement components of rotational and diagonal non-linear exercise, in many cases, these are smaller replicas of machines found in many fitness centers that do not address the need of simulated, non-linear, multi-axial human movement. In fact, most of the devices capture only part of the nonlinear components of movement.
One available device, illustrated in U.S. Pat. No. 4,799,475 utilizes movement that simulates crawling while the user is on hands and knees in a "quadruped" position. The device allows motion through the arc of the frontal plane and provides rotation at the hand or knee contact point. The shortcomings of this device lay in the predetermined magnitude of movement in predominantly two-dimensional patterns. The rotation of the extremities occurs at the axis point which may only affect the most distal joints of the extremities. An additional limitation is that the user has no influence over the magnitude of circular motion since the arc of movement is determined by the track on which the device moves. Resistance is only given in one aspect of the horizontal/frontal plane to adduction/abduction and extension/flexion of the extremities. The movement is controlled by the machine in which no freedom of movement in the sagittal plane occurs, thus, taking away the need for trunk stabilization. This movement is similar to that of a train on a train track that runs up and down and turns left and right. The track is moving in the vertical plane with the ups and downs and in the horizontal plane with the turns, but only a downward force is really needed to keep the train on the track. In essence the movement across any discrete segment of track is still only two dimensional.
Another device, illustrated in U.S. Pat. No. 5,279,530, attempts to exercise the lower extremity in a supine position. The disadvantages of this machine include: there is only linear movement; there is no rotational component; and it is primarily involved in single planar movement. Moreover, the most significant embodiment of this device involves exercise of only the lower extremities and only in a supine position.
In addition to the two devices mentioned, the Diagonal Rotary Patterning exercise machine featured in an article in the Physical Therapy Forum (vol. XIV; number 5; Mar. 10, 1995) was designed to train athletes by employing the use of rotation and diagonal movement using cables. However, the user is sitting down and the need for active trunk stabilization is not really facilitated. The rotation is supplied by a cuff that is fastened about the ankle or wrist, so the axis of rotation is within the longitudinal axis of the extremity, which makes it difficult to facilitate rotation at the proximal joint of the shoulder and hip. The movement occurs predominantly in one plane and isolates training one lower extremity at a time. This machine is large, bulky and appears particularly appropriate for for more vigorous athletic rehabilitation as opposed to the average person seeking rehabilitative, therapeutic exercise.
It would therefore be of significant value in the art to provide a device enabling a user to obtain multidimensional exercise that would allow the user to progress toward full rehabilitation by simulating the difficulty and complexity of real movement. Healthy as well as injured users could benefit from a system of devices that trains the extremities and the trunk musculature in a progressive manner, and that is position selective and, therefore, less stressful to the injured area as well as to the remaining healthy tissue.